Nest predation and climate change as drivers of alternative reproductive tactics in a migratory species

Alternative reproductive tactics enable individuals to choose a reproductive tactic relative to their status and prevailing environmental conditions in a way that increases their fitness. Conspecific brood parasitism, in which females lay eggs in nests of conspecifics, is one example of such behaviour. It has been proposed that when prospects for successful nesting are low and/or costs of reproduction are high, females employ tactics of low cost such as non-breeding and parasitic laying. When environmental conditions are ideal and prospects for success high, females can increase their reproductive effort above typical nesting by laying parasitic eggs prior to initiating their own nest.  , Here, I used this flexible life-history strategy concept and long-term (1994-2022) population level data of the common goldeneye (Bucephala clangula) to study how the rate of parasitic laying varies in relation to variation in nest predation risk and in the timing and length of the breeding season, the latter being measured by the timing of ice breakup., , # Data from: Nest predation and climate change as drivers of alternative reproductive tactics in a migratory species

[https://doi.org/10.5061/dryad.wwpzgmss6](https://doi.org/10.5061/dryad.wwpzgmss6)

The data include annual (1995-2022) values for the following analyses and variables.

In the first sheet (MODEL_VARIABLES) are given data for variables used to analyse among-year variation in the rate of parasitic laying: rate of parasitic laying, ice-out date (IOD), nest predation rate in year t-1, nest predation rate in year t, number of indicated breeding pairs, winter severity index (WSI).

In the second sheet (OTHER_VARIABLES) are given data for variables used in other analyses: proportion of predated eggs for non-parasitized nests (Prop_pred_non-par), proportion of predated eggs for parasitized nests (Prop_pred_par), proportion of eggs failed in other way for non-parasitized nests (Prop_fail_non-par), proportion of eggs failed in other way for parasitized nests (Prop_fail_par), over...

替代生殖策略允许个体依据自身状态与当前环境条件选择适配的生殖策略，从而提升自身演化适合度。种内巢寄生（conspecific brood parasitism）便是这类行为的典型代表：雌性个体将卵产于同种其他个体的巢内。已有研究指出，当成功筑巢的前景不佳且/或生殖成本高昂时，雌性会采取低消耗的生殖策略，例如放弃繁殖或进行寄生产卵；而当环境条件理想、繁殖成功率较高时，雌性可在启动自身筑巢前先行产下寄生卵，进而提升整体生殖投入。

本研究依托这一灵活生活史策略的理论框架，结合1994年至2022年鹊鸭（Bucephala clangula）的种群长期监测数据，探究寄生产卵率如何随巢捕食风险、繁殖季的时序与时长发生变化——其中繁殖季时长以冰融日期作为衡量指标。

# 数据来源：《巢捕食与气候变化作为迁徙物种替代生殖策略的驱动因子》
https://doi.org/10.5061/dryad.wwpzgmss6

本次数据集包含1995年至2022年的年度数据，用于以下分析与变量计算：
在首个工作表（MODEL_VARIABLES）中，提供了用于分析寄生产卵率年际变化的相关变量数据，包括：寄生产卵率、冰融日期（ice-out date, IOD）、前一年巢捕食率、当年巢捕食率、已记录的繁殖对数量、冬季严重程度指数（winter severity index, WSI）。
在第二个工作表（OTHER_VARIABLES）中，提供了其他分析所需的变量数据，包括：非寄生巢的被捕卵比例（Prop_pred_non-par）、寄生巢的被捕卵比例（Prop_pred_par）、非寄生巢的其他类型卵失败比例（Prop_fail_non-par）、寄生巢的其他类型卵失败比例（Prop_fail_par）、over...